Yellow is one of the primary printing ink colors in CMYK process printing. It's a primary color in subtractive color mixing and a secondary color in additive color mixing (the product of red and green). Pure yellow light has a wavelength of approximately 580nm.

Subtractive (printed) yellow		Additive (computer screen) yellow

Yellow is associated with sunlight and warmth. It is the hardest color on our eyes and can lead to fatigue if one is overexposed to the color. Tempers tend to be short in yellow rooms, and it speeds up the metabolism. In smaller doses, yellow can convey much more positive feelings, such as creativity and an easygoing nature. Yellow is the most visible, attention grabbing color, which makes it suitable for safety placcards.